Summary
This work employed manipulative experiments, in conjunction with statistical power analysis, to quantify the effects of human activity on Adélie Penguins (Pygoscelis adeliae) during the incubation and guard phases of their breeding cycle. Two main questions were addressed: (a) What is the minimum, safe distance humans can approach breeding Adélie Penguins before the behaviour and physiology of the birds is significantly affected? and (b) How is the breeding success at Adélie Penguin breeding groups affected by recreational visits and nest checking for scientific purposes? Approaches by a single human to 5 m from breeding penguins interrupted the birds incubation activity, with the potential to cause egg cooling and reduced hatching success. Incubating penguins also became more aggressive and vigilant when approached closely and showed signs of stress-induced salt gland secretion. The heart rates of penguins approached to 5 m were higher than those recorded when birds were undisturbed or when they were exposed to natural disturbances (interactions with conspecifics or South Polar Skuas). The energy expended by incubating penguins when disturbed by close human approaches is estimated to be over twice that expended when penguins were undisturbed. Approaching incubating penguins to 15 m had no measurable effect on their behaviour, but did elevate heart rates significantly above resting, undisturbed rates. Approaches to 30 m had no effect on the birds. Adélie Penguins did not alter their body temperatures in response to human approach. Regular visits to small Adélie Penguin breeding groups (< 70 nests)can reduce breeding success by up to 80 % compared to breeding success at undisturbed groups. This trend was apparent in response to both passive, recreational observation and scientific nest checking. Recommendations are made for minimum approach distances and approach protocols for people to follow when visiting Adélie Penguin colonies. The